1. Field of the Invention
The present invention relates to an organic semiconductor device. Particularly, the present invention relates to an organic semiconductor device comprising an organic semiconductor layer containing a liquid crystalline organic semiconductor material having excellent charge carrier mobility.
2. Description of the Related Art
FIG. 8 is a sectional view showing one example of a conventional organic semiconductor device. A conventional organic semiconductor device 100 comprises a substrate 101, a gate electrode 102, a gate-insulating layer 103, an organic semiconductor layer 104, a source electrode 105 and a drain electrode 106. In the organic semiconductor device having such configuration, the organic semiconductor layer is required to have sufficient charge carrier mobility. Therefore, the organic semiconductor material having high charge carrier mobility is being investigated recently.
As a material having high charge carrier mobility, a liquid crystalline organic semiconductor material is known. For example, by Haarer et al., it is reported that a high carrier mobility of 10−1 cm2/V·s is obtained in meso phase of a long chain triphenylene based compound, which is a typical liquid crystalline organic semiconductor material (for example, see Nature, Vol. 371, p. 141 (1994)). And by Hanna et al., it is reported that a smectic E (SmE) phase of rod-shaped liquid crystal material having phenylnaphthalene skeleton exhibits high charge carrier mobility of 10−2 cm2/V·s (for example, see Appl. Phys. Lett., Vol. 73, No. 25, p. 3733 (1998)). These liquid crystalline organic semiconductor materials are expected as film-forming material constituting a channel region for an organic semiconductor element.